Do you chamber check your ammo? If not, you need to do it. Yes, one case out of 200 may have a bulged base that does not allow it to fully chamber. The question is when you clear the jam can you take that same round and get it to feed the next time? If it is difficult to reopen the gun which you noted then it is most likely a bulged case(s). I use a U-die and still chamber check EVERY round if I will be shooting it in a match or if it is more than just backyard practice drills. Good luck
I have noticed more on my open then limited but the gun prefers lube on lockup with the 10lb springs and if the gun gets dry it doesn't hit battery always.. Slide glide usually keep the gun running very well.
Leo